Spacing mechanism for type-writers.



No. 801,137. PATBNTED OCT. 8, 1905. G. W. DONNING. SPAGING MECHANISM FOR TYPE WRITERS.

APPLICATION FILED FBB.6,1904.

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UNITE STATES PATENT OEEIOE.

GEORGE \V. DONNING, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO HARRY T. AMBROSE, OF ORANGE, NEW JERSEY.

SPACING MECHANISM FOR TYPE-WRITERS.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed February 6, 1904. Serial No. 192,405.

To all 20700710 it "may concern:

Be it known that I, GEORGE W. DONNING, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Spacing Mechanism for Typeriters; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to type-writing machines, and is particularly applicable, though not necessarily restricted, to that class of machines known as book type-writers, wherein a carrying-frame is made to traverse a path back and forth longitudinally over ai'lat platen and carry the printing mechanism in such a way as to permit the usual line-spacing and upon which the printing mechanism is caused to travel back and forth from left to right for the purpose of letter-spacing. The line-spacing is accomplished through means consisting of feed mechanism comprising racks and spring-driven escapement-governed pinions, such as disclosed in my pending application, filed April 26, 1902, Serial No. 104,842. Heretofore much difliculty has been met with, owing to the natural imperfection of the rackand pinion movement causing lost motion and due to wear and other causes. It will be readily understood that an imperfection in the meshing of the teeth of the gear into the rack would cause an uncertainty in the exact positioning of the writing mechanism at some particular line. Its location might even be changed during the writing of a single line or in the writing of a word. I have overcome to such an extent that even when an easily-detected fault is found in one of the teeth of the rack or of the pinion the feed mechanism and its cooperating parts will come to a certain stop at a fixed point and always return to precisely the same position after having been moved.

Theobject of this invention is primarily, then, to take up lost motion between the gearwheel and rack, and by the term taking up lost motion I mean, of course, preventing longitudinal movement of the carriage at a point of faulty engagement between the gear and rack during a period of rest. Asecondary object is to prevent the wear of the rack by cushioning to some extent the engagement This difiiculty of the teeth of the gear with the teeth of the rack.

In the drawings, Figure 1 is a side perspective view of a flat-platen type-writer, some parts being omitted, while others are partly broken away better to illustrate my invention. Fig. 2 is a view in elevation of the driving-gear to which my invention is applicable. Fig. 3 is a section through a part of the carrying-frame of the feed mechanism, showing the driving spring and wheels, and Fig. 4 is a section through the wheels on line 00 w of Fig. 2.

I shall now describe the invention in its broad aspect and at the same time point out the embodiment of these broad principles with reference to the foregoing figures. First, there are a carriage and two toothed members, the latter comprising a rackand a gear-wheel meshing with the rack, one of the toothed members being mounted on the carriage and the other being mounted exterior thereto. These, as will be evident, permit the longitudinal movement of the carriage. In the drawings I have shown the gear-wheel G as mounted on the carriage O and meshing with the stationary rack E exterior to the carriage. There is of course a rack E on each of the parallel track-rails B, and there are likewise two gear -wheels G mounted rigidly on a shaft H, journaled in the standards F of the carriage C.

An actuating element is geared to the rack, so as to transmit to the latter a driving impulse for moving the carriage in a forward direction, and by actuating element I wish to be understood as meaning the spring or other motor or source or reservoir of energy for moving the carriage to effect linespacing. In the present instance said actuating element constitutes a spring N, secured at one end to pin it, projecting inward from one of the standards F and at the other end fastened to the shaft. It is thus geared to the rack through shaft H and gear-wheel G, and the reaction of the impulse so transmitted to the rack operates to drive the carriage forward.

In order to effect the step-by-step movement of the carriage and to afford partial means for taking up lost motion, means are provided whereby there may be intermittingly performed the synchronic actions of preventing the transmission of the driving impulse to the rack, stopping the forward movement of the earriage,and holdingor locking the gear-wheel to its bearings against rotation in one direction. In the present case such means are shown as embodied in one device, the escapepallet P mounted on pivot Q, projecting from the outer face of one of the standards F, and the toothed escape-wheel 0, fixed to the end of the shaft H. Aswill be readily seen, the pallet by engaging with the teeth of the escape-wheel Oat the conclusion of each linespacing movement locks driving -gear G against forward rotation, arrests the forward movement of the carriage, and absolutely removes the pressure of driving-spring Nfrom the rack.

The carriage being brought to rest and the gear-wheel locked against rotation in one direction, it is now possible by suitable means to crowd the carriage to the limit of lost motion against the resistance offered by the means locking the wheel, and thus hold the carriage firmly during the writing of the line. According to my invention the means for so holding or crowding the carriage to the proper limit of lost motion comprises a second gearwheel, mounted similarly to the first and like it meshing with the rack, and a resilient member, distinct from the driving-spring, of a tension constant for the several points of rest of the carriage, such resilient member being arranged at each point of rest and lost motion to urge the second gear-wheel in the direction of locked motion of the first wheel to force or hold the carriage in the direction indicated. Referring to the drawings for the embodiments of these elements, the second gear-wheel is shown at G mounted loosely on shaft H inside and adjacent gear G and of the same diameter and number of teeth as the latter. A pin K projectslaterally from wheel G into a transverse opening L inwheel G and a spring M lyingin such transverse opening bears against the pin, thus resiliently connecting the two wheels and tending to maintain the teeth of wheel Gr in advance of the teeth of wheel G, or, as already stated, urges at each point of rest the wheel G in the di rection in which the palletP prevents rotation of the wheel G. Spring M constitutes the resilient member for forcing one of the teeth of wheel G against one of the abutments at each point of rest and lost motion, so as to retain the carriage at the limit of such lost motion, and since the entire spring rotates with the wheels it is evident that it possesses the same expansive force at each point of rest.

In the operation of the form of my invention illustrated pallet P is to be operated at the conclusion of each spacing movement to lock the driving-gear G to its bearingsagainst forward rotation, necessarily removing the application of the driving impulse from the rack and stopping the forward movement of carriage C. Supposing the pallet to have been so actuated at a point of lost motion, the momentum of the carriage will carry the lattcr to the forward limit of lostmotion, where it will be stopped through the locking action of the pallet by the tooth of wheel G engaging with the tooth on the rack that is just in advance, or the spring M will serve to force the carriage bodily forward with the same result. .In either case the expansive force of the spring h'l. fulcrums, by means of the tooth of wheel (2 against the rack-tooth in rear and the load being applied by shaft H against the center of the wheel G the carriage is retained firmly at the forward limit of lost motion against the resistance of pallet P. \V hen so retained against movement in either direction, the carriage will produce perfect alinement. For the next line-spacing palletP is actuated to unlock the wheel G, driving-spring M is again brought into action and forces the teeth of driving-gear G" forward until the lowermost engages with the tooth of the rack that is just in rear, and the carriage is moved forward one step, when the operations just described are repeated. Thus it will benoted that in a large number of cases at least the tooth of the positively-driven gear Gr will be slightly removed from the racktooth with which it is to engage and that wheel G and spring M will serve to cushion such engagement. This arrangement has a very important efi'ect in preventing wear of the rack.

It will be observed that in the embodiment of my invention illustrated wheels G and G" form two resiliently-connected sections of one wheel G, which is thus adapted to engage first yieldingly and then positively with the rack, or the teeth of wheel (3 may be regarded in this connection as resilient stops maintained normally in advance of the teeth of wheel G to cushion the engagement of the latter with the rack and to take up lost motion.

While I have spoken of the driving-wheel as being locked against rotation in one direction, it must not be inferred that I limit myself to such locking alone.

What I claim as my invention, and desire to secure by Letters Patent, is--- 1. In a type-writer, the combination with a carriage, two toothed members comprising a rack and a gear-wheel meshing with the rack, one of the toothed members being mounted on the carriage and the other being mounted exterior thereto, an actuating element geared to the rack and constructed and arranged to transmit thereto a driving impulse for moving the carriage in a forward direction, and means whereby intermittingly during such movement the carriage may be stopped and the gear-wheel locked to its bearings against rotation in one direction; of a second gearwheel meshing with the rack and mounted with reference to the carriage similarly to the first gear-wheel, and a resilient member distinct from the actuating element and of a tension constant for the several points of rest of the carriage, being Connected with the second gear-wheel and operating at each point of rest to urge the latter in the direction of locked rotation of the first gear-wheel.

2. In a type-writer, the combination with a carriage, two toothed members comprising a rack and a gear-wheel meshing with the rack, one of the toothed members being mounted on the carriage and the other being mounted exterior thereto, an actuating element for moving the carriage in a forward direction, and means whereby intermittingly during such movement the carriage may be stopped and the gear-wheel locked to its bearings against rotation in one direction; of a second gear-wheel meshing with the rack and mounted with reference to the carriage similarly to the first gear-wheel, and a resilient and yielding connection between said gear-wheels urging the second gear-wheel at each point of rest and lost motion in the direction of locked rotation of the first gear-wheel.

3. In a type-writer, the combination with a carriage, a gear-wheel mounted thereon, a rack meshed by the gear-wheel and over which the carriage travels, an actuating element for moving the carriage in a forward direction, and means whereby intermittingly during such movement the carriage may be stopped and the gear-wheel locked to its bearings against rotation in one direction; of a second gear-wheel mounted on the carriage and meshing with the rack, and a resilient device connecting said gear-wheels and urging the second gear-wheel at each point of rest and lost motion in the direction of locked rotation of the first gear-wheel.

4. In a type-writer, the combination with a carriage, a gear-wheel mounted thereon, a rack meshed by the gear-wheel and over which the carriage travels, an actuating element connected to the gear-wheel and driving the carriage therethrough in a forward direction, and means whereby intermittingly during such movement the gear-wheel may be locked to its bearings against forward rotation; of a second gear-wheel mounted on the carriage and meshing with the rack, and a resilient device connecting said gear-wheels and urging the second to have a forward rotation inclependently of the other at each point of rest and lost motion.

5. In a type-writer, the combination with a carriage, a gear-wheel mounted'thereon, a rack meshed by the gear-wheel and over which the carriage travels, an actuating element con nected to the gear-wheel and driving the carriage therethrough in a forward direction, and means whereby intermittingly during such movement of the carriage the gear-wheel may be locked to its bearings against forward rotation; of a second gear-wheel mounted on the carriage in axial alinement with the first and also meshing with the rack, and a resilient device connecting said gear-wheels and urging the second to have a forward rotation independently of the other at each point of rest and lost motion.

6. In a typewriter, the combination with a carriage; of two meshing toothed members, one being mounted on the carriage and the other being mounted exterior thereto, and comprising a rack and a gear-wheel, one of the toothed members being formed in two vertical longitudinal resiliently-connected sections meshing simultaneously with the rack.

7. In a type-writer, the combination with a carriage; of two meshing toothed members, one being mounted on the carriage and the other being mounted exterior thereto, and comprising a rack and a gear-wheel, the latter being formed in two resiliently-connected circular sections meshing simultaneously with the rack.

8. In a typewriter, the combination with a carriage; of two meshing toothed members, one being mounted on the carriage and the other exterior thereto, and comprising a rack and a gear-wheel, the latter comprising two toothed wheels meshing simultaneously with the rack and of an equal number of teeth and mounted in axial alinement, and a spring resiliently connecting the two wheels and tending to force the teeth thereon out of transverse alinement.

9. In a type-writer, the combination with a carriage; and two toothed members, one mounted on the carriage and the other exterior thereto, and comprising a rack and a driving-wheel meshing therewith; of a second gear-wheel meshing simultaneously with the rack and mounted in axial alinement with the first gear-wheel and of the same number of teeth therewith, and a spring between said two wheels tending to maintain the teeth of the second wheel in advance of the teeth of the first.

10. In a type-writer, the combination with a carriage, and two meshing toothed members, one mounted on the carriage and the other exterior thereto, and comprising a rack and a gear-wheel; of a series of resilient stops mounted on one of the toothed members in position to engage with the teeth of the rack, said stops being equal in number to the teeth of said member and maintained out of transverse alinement therewith.

11. In a type-writer, the combination with a carriage, and two meshing toothed members, one mounted on the carriage and the other exterior thereto, and comprising a rack and a gear-wheel; of a series of resilient stops mounted on the gear-wheel in position to engage with the teeth of the rack, said stops being equal in number to the teeth of said wheel and maintained out of transverse alinement therewith.

12. In atype-writer, the combination with a carriage, and two meshing toothed members,

one mounted on the carriage and the other exterior thereto, and comprising a rack and a gear-wheel; ol a series of stops mounted on the gear-wheel in position to engage with the teeth of the rack and equal in number to the teeth thereof, and a resilient connection between the wheel and stops tending to maintain the latter out of transverse alinement with the teeth of said wheel.

13. In a type-writer, the combination with. a carriage, and two toothed members one mounted on the carriage and the other exterior thereto and com prising a rack and a d riving-wheel; of resilient stops mounted on said wheel in advance of the teeth thereof in posi tion to engage with the teeth of the rack, whereby the wheel engages first yieldingly and then positively with the teeth of the rack. 

